Fan Clutch
Fan Clutch TestSpin the fan blade by hand. A light resistance should be felt. If there is no resistance or very high resistance, the minimum and maximum fan speeds must be checked as follows:
Minimum Speed Fan Clutch Requirement Test
1. Use a suitable marker to mark the water pump pulley, one of the fan blade bolts, and the crankshaft pulley.
2. Connect a tachometer to the engine.
3. Install a throttle adjusting tool.
4. Connect a digital photoelectric tachometer.
5. WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation. Failure to follow these instructions may result in personal injury. Start the engine and run it at approximately 1,500 rpm until the normal operating temperature has been achieved.
6. Adjust the engine speed to 2,300 rpm.
7. Adjust the strobe light to 3,000 rpm and aim it at the water pump pulley. Adjust the engine speed until the light flash and the water pump pulley mark are synchronized.
8. Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade retaining bolt (fan blade appears to stand still).
9. The fan blade speed must not be greater than 1,500 rpm at 3,000 water pump rpm.
10. Turn the engine off.
11. If the fan blade speed was greater than 1,500 rpm, install a new fan clutch.
Maximum Speed Fan Clutch Requirement Test
1. Perform Steps 1 through 5 of the Minimum Speed Fan Clutch Requirement Test.
2. NOTE: The engine temperature should be above 96°C (205°F) for maximum fan speed.
Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille. This will raise the temperature of the air striking the fan clutch and should cause the fan to operate at maximum speed.
3. Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
4. Adjust the strobe light to 3,000 rpm.
5. WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation. Failure to follow these instructions may result in personal injury.
Start the engine and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
6. Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade retaining bolt (fan blade appears to stand still).
7. If the fan blade speed is less than 2,300 rpm, install a new fan clutch.